1. Field of the Invention
This invention relates generally to aqueous polymer thick film conductive compositions containing conductive metal, carbon or graphite particles. The compositions are particularly useful for screening into electrical circuits and for formulation into human contact electrodes.
2. Brief Description of the Art
In the past, water-based conductive polymer thick film formulations have typically exhibited poor rheology, poor adhesion and poor flexibility when printed and cured on polyester or polycarbonate films. They also have not offered the relatively low electrical resistance that is achievable with solvent based formulas.
In view of the above, new aqueous compositions which provide a solution to the above problems while containing a reduced amount of organic solvents, relative to conventional solvent-based thick film formulations, would be highly desired by the polymer thick film manufacturing community. The present invention provides one solution to this problem. This invention relates to the use of water soluble thermoplastic polymers in a water-based polymer thick film-forming compositions to impart smooth, easily spreadable coating qualities to the formulation.